Known in the past has been an internal combustion engine wherein operating members (stopper pins) provided at connecting rods are made to operate by supplying hydraulic oil from an oil feed device through a main gallery, crank journals, and crankpins to the operating members (for example, PLT 1). In such an internal combustion engine, the hydraulic oil path supplying oil for making the operating members operate is made a single path and the load of the oil feed device is reduced by supplying the hydraulic oil path with hydraulic oil only when making the operating members operate.